This thesis aims to investigate the consequences of a judgement issued by UK Supreme Court in November 2021, known within the shipping industry as the "CMA CGM Libra" case. This case is perceived by the industry to have affected hte the understanding of the concept of seaworthiness and due diligence, as they should be understood within the context of the Hague Rules and Hague Visby Rules.  The focus lies on the understanding of these two concepts within an English as well as Swedish context, in order to further conclude whether the Judgement may have changed the definitioin of these concepts in any way; from the perspecteve of English as well as Swedish maritime law. This also includes a thorough discussion about the extent of influence English maritime law has on Swedish maritime law, if any.  This text is suitable for anyone with an intererst in or objective to learn more about seaworthines and due diligence as these concepts shall be understood from an English and/or Swedish point of view, and/or in getting better aquainted with the reasoning of the UK Supreme Court in the Libra judgement. As mentioned, the relationship between the two legal systems (including Denmark and Norway) will also be discussed. Students of maritime law will likely be best suited to read and understand this thesis and the conclusions thereof.